The manufacture of advanced, high-speed integrated circuits demands advanced technologies capable of supporting systems that include tens or hundreds of millions of active devices. Such technologies support market demands for ever-increasing system performance, feature sets, and system capabilities. Silicon on Insulator (SOI) is one such technology capable of implementing the feature and speed requirements of advanced integrated circuits. SOI offers reduced parasitic circuit activities and unwanted electrical connections, thus providing benefits in terms of reduced capacitance and increased device speed. SOI is also capable of significantly improving power consumption in comparison to traditional bulk silicon technologies.
Field-effect transistor (FET) devices have been used to implement logic circuitry and memory devices. In the FET, current flows along a semiconductor path called the channel. At one end of the channel, there is an electrode called the source. At the other end of the channel, there is an electrode called the drain. The source/drain regions can be doped with either N-type or P-type dopants; the FET devices are designed such that the carriers are either electrons (NFETs) or holes (PFETs). The FET devices act as switches that are controlled by a voltage applied to the gate. When the voltage applied to the gate is set appropriately, current can easily flow between the source and drain of the FET device; the FET device is effectively a closed switch. Conversely, when the voltage applied to the gate is set at a different level, current cannot easily flow between the source and the drain, and the FET device behaves as an open switch.
Field-effect transistors can be classified into planar field-effect transistors and 3D (vertical) field-effect transistors. In the case of planar field-effect transistors, the channel region is formed parallel to a substrate surface, which can contain the active regions of multiple electronic semiconductor components. One such type of 3D field-effect transistor is the fin-type field-effect transistor (finFET), in which case, the channel connecting the source and drain is a thin, fin-like structure extending perpendicularly out of the base substrate.
In modern electronic designs, there are many factors to consider that involve design tradeoffs. These factors include power consumption during operation, power consumption during standby (or sleep) modes, and device performance (including switching speed). Additionally, circuit density is becoming increasingly important for portable electronic devices. Hence the ability to fit more transistors within a given area is another desirable feature of modern integrated circuits. Often, at least some of these factors involve compromises; for example, improving performance in one area (e.g. device speed) comes at the expense of performance in another area (e.g. power consumption), rendering integrated circuit design increasingly challenging.